ARS microbiologist Ken Bischoff has developed a
shake-flask model to simulate the bacterial outbreaks that can contaminate
ethanol plants and cut yields as much as 27 percent. Click the image for
more information about it.

Cellulosic Ethanol: Expanding Options, Identifying
Obstacles

Agricultural Research Service (ARS)
scientists are figuring out how to turn wheat straw into ethanol
gold, and learning more about the bacteria that can
infect ethanol plants and interfere with fuel production.

Saha found he could access and ferment almost all the plant sugars in the
biofeedstock when it was pretreated with alkaline peroxide and then broken down
by enzymes. This process released even hard-to-reach sugars in plant cell
walls, which significantly boosted the overall ethanol output to around 93
gallons per ton of wheat straw.

But the same environments that facilitate fermentation can also nurture
microorganisms that infect ethanol production facilities and
disrupt output. ARS geneticist
Tim
Leathers collected bacteria from samples at commercial ethanol facilities,
including a wet-mill facility that had never been dosed with antibiotics and a
dry-grind facility that periodically dosed with antibiotics after bacterial
outbreaks. He found that most of the bacterial isolates he collected from both
facilities were different types of lactic acid bacteria.

Meanwhile, ARS microbiologist
Ken
Bischoff developed a model for simulating bacterial contamination and
infection. He found that when test cultures were inoculated with
Lactobacillus fermentumone of the most common sources of bacterial
infections in ethanol plantsethanol yields decreased by 27 percent.
Sometimes the infection could be cured with antibiotics, but he
also found one bacterial strain that was already resistant to treatment.